JP3460676B2 - Control device for infinitely variable speed ratio transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an infinitely variable transmission continuously variable transmission mounted on a vehicle or the like.

[0002]

2. Description of the Related Art A continuously variable transmission having a continuously variable transmission ratio and a planetary gear mechanism combined with a constant transmission mechanism allows the transmission ratio to be changed to infinity. Hereinafter, referred to as "IVT".) Is known. Such a transmission is disclosed, for example, in JP-A-63-219.
No. 956.

Generally, in an IVT, a toroidal type continuously variable transmission mechanism and a constant transmission mechanism are connected in parallel to an IVT input shaft connected to an engine, and an output shaft of the continuously variable transmission mechanism is a planetary gear mechanism. The output shaft of the constant speed change mechanism is connected to the sun gear via the power circulation mode clutch, and is connected to the carrier of the planetary gear mechanism. The ring gear of the planetary gear mechanism is connected to the output shaft of the IVT.

With such a structure, when the power circulation mode clutch is engaged, the output shaft of the IVT rotates by receiving the output rotation of the continuously variable transmission and the output rotation of the constant transmission simultaneously. By changing the gear ratio of the continuously variable transmission mechanism, the total gear ratio of the IVT can be continuously changed to infinity. As shown in FIG. 24, the power circulation mode clutch is engaged and the direct coupling mode clutch is engaged. By releasing, the total speed ratio (hereinafter referred to as IVT ratio ii unit input shaft speed / unit output shaft speed) changes from a negative value to a positive value in accordance with the difference in the speed ratio between the continuously variable transmission mechanism and the constant transmission mechanism. Up to the value of infinity (1 / g = 0, which is called geared neutral point GNP), the power circulation mode for continuously performing the shift control, and the power circulation mode clutch is released while the direct connection mode is released. Speed ratio of the continuously variable transmission mechanism to engage the clutch (hereinafter, CVT ratio ics) two operating modes of the direct mode for shift control can be selectively used in accordance with.

At the geared neutral point GNP in the power circulation mode, the stopped state of the vehicle can be maintained, and from this stopped state, the IVT ratio ii (= CVT ratio ic).
It is possible to start the vehicle by changing the above, and a starting element such as a torque converter such as the conventional automatic transmission is unnecessary.

[0006]

By the way, when a vehicle equipped with such an IVT is stopped in the P range or the N range, the gear ratio of the continuously variable transmission mechanism becomes a value that realizes the geared neutral point. However, if this speed ratio deviates from the geared neutral point, the power circulation mode clutch is released to prevent power from being accidentally transmitted to the drive wheels.

When the driver operates the select lever to the D range or the R range in order to start the vehicle from this state, the power circulation mode clutch is engaged and the IVT
Power is transmitted to the output shaft. At this time, if the gear ratio of the continuously variable transmission has a value that realizes the geared neutral point, the vehicle is maintained in a stopped state, and a shock due to a difference in the rotational speed of the clutch does not occur.

On the other hand, when a toroidal type is adopted as the continuously variable transmission mechanism, there is a phenomenon called torque shift in which the gear ratio varies due to fluctuations in input torque and rattling of various parts. As shown in FIG. And the tilt angle (gear ratio) of the power roller has a hysteresis, and even if the number of steps of the step motor is set so as to reach the geared neutral point GNP when there is no load when the input torque is 0, The tilt angle of the power roller = actual gear ratio may fluctuate within a fluctuation range Δφ in the figure.

As will be described later, this torque shift can be roughly classified into three main factors. First, in FIG. 4, when the power roller 20 is offset with respect to the input torque, the pivot shaft 24 falls down. Occurs in the vertical direction in the figure, the axial displacement of the trunnion 23 is reduced by the amount of tilt of the pivot shaft 24 with respect to the actual offset amount of the power roller 20, and the actual mechanical feedback amount also changes. The power roller 20 tilts excessively due to the change in the feedback amount, and the gear shift becomes excessive, which is the first factor of the torque shift.

The second cause is the input / output disks 21, 22.
Also, since the torque is transmitted by the power roller 20, the loading cam device generates a clamping pressure according to the input torque, and the power roller 20 causes the input / output disk 21 to move.
The power roller 20 is held and pressed by the power roller 20.
Receives a thrust force in the direction of being pushed out from between the input / output disks 21 and 22 in FIG. Here, the trunnion 2 that supports the power rollers 20, 20 facing each other
Since 3 and 23 are connected above and below the pivot shaft 24 via a swingable link (not shown), the trunnion 23 is deformed by the thrust force with this connecting point as a fulcrum, and the trunnion 23 is , 32, the tilt angle of the power roller 20 deviates from the target tilt angle, which is the second factor of the torque shift.

Next, the third factor is that the power roller 20 is sandwiched and pressed by the input / output disks 21 and 22 in order to transmit torque, but the input / output disk 21 is pressed against the output disk 22 side. As a result, the disc is deformed.

Due to this deformation, the contact position between the power roller 20 and the input / output disks 21, 22 changes, so that the pivot shaft 24 swings, and the trunnion 23 displaces in the axial direction in response to this swing. The gear is changed to. This is the third factor of torque shift.

The above torque shift has the following hysteresis.

When the CVT ratio is in the vicinity of the geared neutral point GNP and the input torque changes including 0, the direction of the input torque to the continuously variable transmission mechanism 2 is reversed at the geared neutral point GNP. Therefore, as shown in FIG. 23, a hysteresis region occurs in the torque shift.

As shown in FIG. 4, when the power roller 20 is supported via the pivot shaft 24 as the toroidal type continuously variable transmission mechanism 2, a bearing is interposed between the base end of the pivot shaft 24 and the trunnion 23. Thus, the pivot shaft 24 is swingably supported.

Since this bearing has radial backlash (clearance) and friction, the pivot shaft 24 does not swing until the torque applied to the power roller 20 becomes larger than the backlash and friction.

Therefore, in the vicinity of the geared neutral point GNP, the pivot shaft 24 does not swing until the absolute value of the input torque becomes larger than the play and friction around the pivot shaft 24 after the direction of the input torque is reversed. Therefore, hysteresis occurs in the torque shift.

Therefore, as shown in FIG. 23, on the increase side of the input torque (direction from negative to positive), the tilt angle of the power roller 20 decreases along the line T + in the figure, while the input torque decreases. On the side (direction from positive to negative), there is a hysteresis region in which the tilt angle of the power roller 20 increases along the line T- in the figure.

Even if an attempt is made to maintain the geared neutral point GNP on the line T + in the figure, the tilt angle that can be taken when the input torque = 0 is the variation range Δφ in the figure.
It has a characteristic that the IVT ratio deviates from the geared neutral point GNP because it becomes indefinite within (a value that the tilt angle can take when input torque = 0).

However, in the above conventional example, if the actual gear ratio deviates from the gear ratio that realizes the geared neutral point GNP due to the hysteresis of the torque shift of the toroidal type continuously variable transmission mechanism, IV
The total gear ratio of T does not become infinite, and a shock occurs due to the difference in rotation speed when the power circulation mode clutch is engaged,
If the shift ratio is large, there is a problem that the engine is stopped.

Further, when the power transmission mode clutch is engaged, if the total gear ratio deviates from the traveling direction of the vehicle expected by the driver, creep torque is generated in the opposite traveling direction to the expected traveling direction. This will cause the driver to feel uncomfortable. For example, in FIG. 24, the gear ratio (C
If the VT ratio) is deviated from the geared neutral point GNP to the reverse side (Hi side), the reverse side creep torque is generated despite the driver moving the select lever from the N range to the D range. It will end up.

The present invention has been made in view of the above-mentioned problems of the prior art. In an infinitely variable transmission continuously variable transmission,
The purpose of the present invention is to prevent a shock and a feeling of strangeness when the select lever is operated due to the total gear ratio deviating from infinity when the vehicle is stopped.

[0023]

According to a first aspect of the invention, a unit input shaft connected to an engine is connected to a toroidal type continuously variable transmission mechanism capable of continuously changing a gear ratio and a constant transmission mechanism. At the same time, the output shafts of the continuously variable transmission mechanism and the constant transmission mechanism are connected to the unit output shaft through the planetary gear mechanism, the power circulation mode clutch and the direct coupling mode clutch, and the infinite gear ratio continuously variable transmission and the position of the select lever are set. Shift position detecting means for detecting, an actuator for changing the gear ratio of the continuously variable transmission mechanism, and a total gear ratio of an infinite gear ratio continuously variable transmission by controlling the actuator according to the operating state of the vehicle In the control device for an infinitely variable transmission ratio continuously variable transmission, the transmission gear ratio control means determines whether the shift position detection means is in the N range or the P range. Upon detection of the operation to the D range or R range, after temporarily moving the position of the actuator, it is driven to a position to realize the geared neutral point.

According to the second aspect of the invention, a toroidal type continuously variable transmission capable of continuously changing a gear ratio and a constant transmission mechanism are respectively connected to a unit input shaft connected to an engine, and a continuously variable transmission is provided. A continuously variable transmission with an infinite gear ratio in which the output shafts of the speed change mechanism and the constant speed change mechanism are connected to the unit output shaft via a planetary gear mechanism, a power circulation mode clutch and a direct coupling mode clutch, and a shift position for detecting the position of the select lever. A detection unit, an actuator that changes the gear ratio of the continuously variable transmission mechanism, and a gear ratio control that changes the total gear ratio of the continuously variable transmission with infinite gear ratio by controlling the actuator according to the operating state of the vehicle. In a control device for an infinitely variable transmission ratio continuously variable transmission, the transmission ratio control means is characterized in that the shift position detecting means has an N range or a P range to a D range. Rui, upon detecting an operation to the R-range, after temporarily moving the position corresponding to the position of the actuator to the geared neutral point, driven to a position to realize the geared neutral point during starting.

The third invention is the first or second invention.
In the invention, the gear ratio control means uses at least torque shift when the shift position detecting means detects an operation from the N range or P range to the D range or R range and temporarily moves the position of the actuator. Move the actuator to a position according to the amount of hysteresis.

A fourth invention is the second or third invention.
In the invention, when the shift position detecting means detects an operation from the N range or P range to the D range or R range, the gear ratio control means sets the driving direction of the actuator according to the traveling direction of the vehicle. To do.

In a fifth aspect based on the fourth aspect, the gear ratio control means operates the actuator when the shift position detecting means detects an operation from the N range or the P range to the D range. The drive position is driven from a position corresponding to the geared neutral point to a position preset to a large side of the gear ratio of the continuously variable transmission mechanism, and then to a position that realizes the geared neutral point when starting.

According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the gear ratio control means operates the actuator when the shift position detecting means detects an operation from the N range or the P range to the R range. The drive position is driven from a position corresponding to the geared neutral point to a position preset to a smaller side of the gear ratio of the continuously variable transmission mechanism, and then to a position corresponding to the geared neutral point when starting.

In the seventh aspect of the invention, a toroidal type continuously variable transmission mechanism capable of continuously changing a gear ratio and a constant transmission mechanism are respectively connected to a unit input shaft connected to an engine, and a continuously variable transmission mechanism is also provided. Detects the position of the select lever or switch and an infinite gear ratio continuously variable transmission in which the output shafts of the speed change mechanism and the constant speed change mechanism are connected to the unit output shaft via a planetary gear mechanism, a power circulation mode clutch and a direct coupling mode clutch. A shift position detecting means, an actuator for changing the gear ratio of the continuously variable transmission mechanism, and a gear shift for changing the total gear ratio of an infinite gear ratio continuously variable transmission by controlling the actuator according to the operating state of the vehicle. In a control device for an infinitely variable gear ratio continuously variable transmission including a ratio control means,
When the shift position detecting means detects an operation from the N range or the P range to the D range or the R range, the gear ratio control means drives the actuator to a position that realizes a geared neutral point when the input torque is 0. However, the position for realizing this geared neutral point is set at a position where the creep torque according to the traveling direction can be controlled when the input torque changes in the traveling direction set by the shift position detecting means. .

In the eighth invention, a toroidal type continuously variable transmission mechanism capable of continuously changing a gear ratio and a constant transmission mechanism are respectively connected to a unit input shaft connected to an engine, and a continuously variable transmission mechanism is also provided. Detects the position of the select lever or switch and an infinite gear ratio continuously variable transmission in which the output shafts of the speed change mechanism and the constant speed change mechanism are connected to the unit output shaft via a planetary gear mechanism, a power circulation mode clutch and a direct coupling mode clutch. A shift position detecting means, an actuator for changing the gear ratio of the continuously variable transmission mechanism, and a gear shift for changing the total gear ratio of an infinite gear ratio continuously variable transmission by controlling the actuator according to the operating state of the vehicle. In a control device for an infinitely variable gear ratio continuously variable transmission including a ratio control means,
When the shift position detecting means detects an operation from the N range or the P range to the D range or the R range, the gear ratio control means drives the actuator to a position that realizes a geared neutral point with an increased input torque. To do.

Further, in a ninth aspect based on the eighth aspect, the gear ratio control means sets a position where a geared neutral point is realized in a state where the input torque is increased, outside a hysteresis region due to torque shift. Alternatively, set it to the end point of the hysteresis area.

In a tenth aspect based on the ninth aspect, the gear ratio control means sets the position where the geared neutral point is realized with the input torque increased to the input torque to the continuously variable transmission mechanism. Set according to the direction.

[0033]

Therefore, according to the first aspect of the present invention, in a continuously variable transmission having an infinite transmission ratio using a toroidal type continuously variable transmission mechanism, a continuously variable transmission is provided near a geared neutral point where the total transmission ratio becomes infinite. There is hysteresis corresponding to the torque shift in the relationship between the gear ratio of the mechanism and the torque that acts on the continuously variable transmission mechanism. When the vehicle is started by ND select or NR select, temporarily move the position of the actuator that changes the gear ratio of the continuously variable transmission mechanism, and then drive to a position that realizes the geared neutral point. Then, set the gear ratio, which was indefinite due to the hysteresis caused by the torque shift, to the minimum value or the maximum value of the fluctuation range of the hysteresis, and this hysteresis prevents the gear ratio of the continuously variable transmission from deviating from the geared neutral point. It is possible to prevent the shock and the uncomfortable feeling at the time of operating the select lever as in the conventional example described above, and it is possible to improve the starting performance of the continuously variable transmission with an infinite gear ratio.

The second aspect of the present invention is an infinitely variable continuously variable transmission using a toroidal type continuously variable transmission mechanism, wherein the continuously variable transmission mechanism is provided near a geared neutral point at which the total gear ratio becomes infinite. There is hysteresis corresponding to the torque shift in the relationship between the gear ratio and the torque that acts on the continuously variable transmission mechanism. When the vehicle is started by ND select or NR select, the position of the actuator that changes the gear ratio of the continuously variable transmission mechanism is temporarily moved from the position where the geared neutral point is realized while the vehicle is stopped. By driving to the position that realizes the geared neutral point, the actuator position is at the position corresponding to the geared neutral point,
The gear ratio, which was indefinite due to the hysteresis caused by the torque shift, is set to the minimum value or the maximum value of the hysteresis fluctuation range, and this hysteresis ensures that the gear ratio of the continuously variable transmission mechanism does not deviate from the geared neutral point. In addition, it is possible to prevent shock and discomfort when the select lever is operated as in the conventional example, and it is possible to improve the starting performance of a continuously variable transmission with an infinite gear ratio.

The third aspect of the present invention detects the operation from the N range or the P range to the D range or the R range and temporarily moves the position of the actuator, depending on at least the magnitude of hysteresis due to the torque shift. Drive the actuator to a position that achieves the geared neutral point when the vehicle starts, resulting in a torque shift even though the position of the actuator corresponds to the geared neutral point. The gear ratio that was indefinite due to the hysteresis is set to the minimum value or the maximum value of the hysteresis fluctuation range in the gear ratio that achieves the geared neutral point when the input torque is applied to the continuously variable transmission and the vehicle starts. , The shifting of the continuously variable transmission by this hysteresis Can be reliably prevented from shifting from the geared neutral point, and shock and discomfort during the operation of the select lever as in the conventional example can be prevented, and the starting performance of a continuously variable transmission with an infinite gear ratio can be improved. It will be possible.

In the fourth aspect of the invention, when an operation from the N range or the P range to the D range or the R range is detected, the driving direction of the actuator is set according to the traveling direction of the vehicle. Therefore, the geared neutral point is set. Since the direction of the input torque of the continuously variable transmission mechanism is different between the case of moving forward and the case of moving backward, the direction in which the gear ratio changes due to the torque shift is also different. The geared neutral point can be reliably achieved when starting.

Further, in the fifth aspect of the invention, when the vehicle is started to the forward side by the operation from the N range to the D range, the drive position of the actuator is changed from the position corresponding to the geared neutral point to the gear ratio of the continuously variable transmission mechanism. After driving toward the preset position on the large side of the vehicle, the gear was moved to a position where the geared neutral point was realized when starting, so it was undefined near the geared neutral point due to hysteresis due to torque shift. In addition to being able to set the gear ratio of the continuously variable transmission to the geared neutral point without fail and starting the vehicle forward, the direction in which the actuator is temporarily moved is set to the higher side of the gear ratio of the continuously variable transmission. , Since the large side of this gear ratio is the total gear ratio from the geared neutral point to the forward side,
Even if the power circulation mode clutch is engaged before the position of the actuator reaches the geared neutral point used for starting, the vehicle is propelled to the forward side set by the select lever. Therefore, it is possible to reliably prevent the driving force from being transmitted to the side opposite to the traveling direction of the vehicle expected by the driver.

In the sixth aspect of the invention, when the N-range to the R-range is operated to move backward, the drive position of the actuator is changed from the position corresponding to the geared neutral point to the gear ratio of the continuously variable transmission mechanism. After driving toward the preset position on the small side of, the drive to the position that achieves the geared neutral point at the time of starting, was indefinite near the geared neutral point due to hysteresis due to torque shift. The gear ratio of the continuously variable transmission can be set to the geared neutral point before starting to the forward side, and the direction of temporarily moving the actuator is set to the smaller side of the gear ratio of the continuously variable transmission. , Since the small side of this gear ratio is the total gear ratio from the geared neutral point to the reverse side,
Even if the power circulation mode clutch is engaged before the position of the actuator reaches the geared neutral point used for starting, the vehicle is propelled to the reverse side set by the select lever. Therefore, it is possible to reliably prevent the driving force from being transmitted to the side opposite to the traveling direction of the vehicle expected by the driver.

Further, in the seventh aspect of the invention, the gear ratio of the continuously variable transmission is set as a geared neutral point when the input torque is 0 at the time of starting, and at this gear ratio, the gear ratio is directed in the traveling direction. When the input torque changes, the creep torque according to the traveling direction is set to be controllable. Therefore, by controlling the engagement capacity of the power circulation mode clutch, the creep torque is controlled with high reproducibility. It becomes possible.

Further, in the eighth aspect of the invention, the gear ratio of the continuously variable transmission is set as the geared neutral point when the input torque is increased when the vehicle is started.
By avoiding the hysteresis of the continuously variable transmission mechanism which becomes noticeable when there is no load, by setting the geared neutral point accurately and gradually engaging the power circulation mode clutch, it becomes possible to smoothly start the vehicle.

In the ninth aspect of the invention, the effect of the hysteresis region is set by setting the position for realizing the geared neutral point in the state where the input torque is increased to the outside of the hysteresis region due to the torque shift or the end point of the hysteresis region. It is possible to perform the shift control with high responsiveness without being affected.

In the tenth aspect of the invention, the geared neutral point setting position is set outside the hysteresis region due to the torque shift or at the end point of the hysteresis region, in other words, the direction of the input torque of the continuously variable transmission mechanism.
By setting according to the traveling direction of the vehicle, it becomes possible to perform the shift control with high responsiveness without being affected by the hysteresis region for each of forward movement and backward movement.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

1 to 3 show a schematic structure of an infinitely variable transmission continuously variable transmission (hereinafter referred to as "IVT") to which the present invention is applied. The IVT shown here is of a so-called half toroidal type. It is configured using the continuously variable transmission mechanism 2.

As shown in FIGS. 1 to 3, the IVT has an IVT input shaft 1 (unit input shaft) connected to a crankshaft of an engine, and a continuously variable transmission mechanism 2 capable of continuously changing a gear ratio. A constant speed change mechanism 3 (speed reducer) including a gear 3a and a gear 3b is connected in parallel, and these output shafts 4 and 3c are coaxially arranged on the IVT output shaft 6 (unit output shaft) side. In addition, the output shafts 4 and 3c are connected by the planetary gear mechanism 5.

The output shaft 4 of the continuously variable transmission mechanism 2 transmits the driving force between the output shaft 4 of the continuously variable transmission mechanism 2 and the output sprocket 2a of the continuously variable transmission mechanism 2 through the sprocket 4a and the chain 40, and one end of the output shaft 4 is a planet. A direct coupling mode clutch 10 that is coupled to the sun gear 5a of the gear mechanism 5 and that is selectively engaged with the IVT output shaft 6 is provided at the other end.

On the other hand, the output shaft 3c of the constant speed change mechanism 3 is connected to the carrier 5b of the planetary gear mechanism 5 via the power circulation mode clutch 9, and the ring gear 5c meshing with the pinion of the carrier 5b is the IVT output shaft. Is combined with 6.

A transmission output gear 7 is provided on the output shaft 6 of the IVT, and the transmission output gear 7 meshes with the final gear 12 of the differential gear 8 so that the differential gear 8 has a predetermined total reduction ratio.
The driving force is transmitted to the drive shafts 11a and 11b coupled with the drive shafts.

The continuously variable transmission mechanism 2 includes two sets of input discs 2.
1. The output disc 22 is a double-cavity toroidal-type continuously variable transmission mechanism that holds and presses the power roller 20, and the power roller 20 is rotatably supported by a trunnion to be described later. By changing the tilt angle of the trunnion according to the number of steps (rotation angle = driving position) of the step motor 36 (actuator) described later, the gear ratio of the continuously variable transmission mechanism 2, and further the total gear ratio of the IVT. Can be changed steplessly.

The gear ratio (CVT ratio) of the continuously variable transmission mechanism 2 and I
The relationship with the reciprocal of the total gear ratio of VT (1 / IVT ratio) is shown in FIG.
As shown in 4.

As shown in this figure, in the power circulation mode in which the power circulation mode clutch 9 is engaged and the direct coupling mode clutch 10 is disengaged, according to the difference in the gear ratio between the continuously variable transmission mechanism 2 and the constant transmission mechanism 3. , The gear ratio is infinite both forward and backward (geared neutral point GNP in the figure)
Can be changed continuously. Further, in the direct coupling mode in which the power circulation mode clutch 9 is released and the direct coupling mode clutch 10 is engaged, the shift control according to the gear ratio of the continuously variable transmission mechanism 2 can be performed.

As shown in FIG. 1, the toroidal type continuously variable transmission mechanism 2 includes two sets of an input disk 21 and an output disk 2.
2 is a double-cavity half-toroidal type that holds and presses the power rollers 20 and 20, respectively.
The output sprocket 2 a interposed between the pair of output disks 22 is connected to the IVT input shafts 1, C via the chain 40.
It is connected to a sprocket 4a formed on the output shaft 4 of the continuously variable transmission on the side of the IVT output shaft 6 arranged in parallel with the VT input shaft 1b.

Further, as shown in FIG. 2, the IVT input shaft 1 and the CVT input shaft 1b are coaxially arranged and connected in the rotational direction via the loading cam 13, so that the IVT input shaft 1 Is coupled to the crankshaft of the engine and forms the gear 3a of the constant speed change mechanism 3, and the CVT input shaft 1b includes two sets of input disks 21, 21.
The power rollers 20 and 20 are sandwiched and pressed between the input and output disks by the axial pressing force generated by the loading cam 13 according to the input torque from the IVT input shaft 1.

The continuously variable transmission mechanism 2 includes two sets of input discs 2.
1. A toroidal type continuously variable transmission mechanism having a double cavity for sandwiching and pressing the power roller 20 between the output disc 22 and the output disk 22, and the power roller 20 is rotatably supported by a trunnion 23 described later. This trunnion 23
By changing the tilt angle of the step motor 36 according to the number of steps (rotation angle) of the step motor 36 described later, the step ratio of the continuously variable transmission mechanism 2, and further the total speed ratio of the IVT can be changed steplessly. it can.

The gear ratio (CVT ratio) of the continuously variable transmission 2 and I
The relationship with the reciprocal of the total gear ratio of VT (1 / IVT ratio) is shown in FIG.
As shown in 4.

As shown in FIG. 24, in the power circulation mode in which the power circulation mode clutch 9 is engaged and the direct coupling mode clutch 10 is disengaged, a change in gear ratio between the continuously variable transmission mechanism 2 and the constant transmission mechanism 3 is performed. Thus, the gear ratio can be continuously changed including infinity (geared neutral point in the figure) on both the forward and backward sides. Further, the power circulation mode clutch 9 is released, and the direct coupling mode clutch 1
In the direct connection mode in which 0 is engaged, it is possible to perform gear shift control according to the gear ratio of the continuously variable transmission mechanism 2.

Here, the transmission mechanism and mechanical feedback mechanism of the toroidal type continuously variable transmission mechanism 2 will be described.

The power roller 20, which is sandwiched between the input / output disks 21 and 22, and which is disposed at the opposite position,
20 is a trunnion 23 on the base end side, as shown in FIG.
It is swingably supported by 23 and is pivotally supported by pivot shafts 24, 24 provided with a predetermined offset. A bearing (not shown) such as a needle bearing is interposed between the base end of the pivot shaft 24 and the trunnion 23.

In FIG. 4, the trunnion 23, which swingably supports the base end side of the pivot shaft 24, has a lower portion coupled to the hydraulic cylinder 30 and is supported so as to be displaceable in the axial direction and rotatable about the axis. . At one lower end of the plurality of trunnions 23, a tilt angle, that is, an actual gear ratio (actual CVT ratio) and an axial displacement of the trunnion 23 are combined and fed back to a shift control valve 46 described later. A precess cam 35 is provided for this purpose.

The hydraulic cylinder 30 is provided with upper and lower oil chambers 30A and 30B defined by a piston 31. As shown in FIG. 4, the trunnions 23 and 23 arranged opposite to each other.
The hydraulic cylinders 30 and 30 of the trunnion 2 are set such that the arrangements of the oil chambers 30A and 30B are mutually reversed.
3, 23 are driven in mutually opposite directions. The trunnions 23, 23 are connected to each other via a swingable link (not shown) above and below the pivot shaft 24, and the trunnions 23, 23 are displaced in opposite directions.

Therefore, when the oil pressure in the oil chamber 30A is increased and at the same time the oil pressure in the oil chamber 30B is decreased, the trunnion 23 on the right side in the figure rises while the trunnion 23 on the left side in the figure increases.
Is lowered and the power rollers 20, 20 are on the Lo side (gear ratio =
The gear is tilted (displaced around the axis of the trunnion 23) to the large side) to change gears. At this time, the rotary shaft 20 of the power roller 20 is rotated.
c and the rotation axis 1c of the input / output disk are aligned, the pivot shaft 2 is moved in accordance with the axial displacement of the trunnion 23.
Since 4 swings around the axis 24c, the power roller 20
While maintaining the tilted state, the rotary shaft 20c can be aligned with the rotary shaft 1c of the input / output disk to transmit the driving force.

On the other hand, when the oil pressure in the oil chamber 30A is reduced and at the same time the oil pressure in the oil chamber 30B is increased, the reverse of the above, the trunnion 23 on the right side in the figure descends, while the trunnion 23 on the left side in the figure rises. The power rollers 20, 20
Shifts to the Hi side (gear ratio = small side).

As shown in FIG. 4, the recess cam 35 is provided with a cam groove or cam surface having a predetermined inclination in the circumferential direction, and the feedback link 38 swingable on the cam groove or cam surface. One end of the slide contact.

The feedback link 38 is, for example, L
It is formed in a letter shape and is swingably supported about a swing shaft 39. One end is in sliding contact with the cam groove or the cam surface, and the other end is engaged with one end of the speed change link 37. The rotation amount of the trunnion 23, that is, the tilt angle and the axial displacement amount are combined and transmitted to one end of the speed change link 37.

As shown in FIG. 5, the speed change link 37 is connected to the end of the spool 46S of the shift control valve 46 at the center, while the feedback link 3 is connected.
8 is connected to the step motor 36 at the opposite end, and the speed change link 37 displaces the spool 46S of the shift control valve 46 in the axial direction by driving the step motor 36, while rotating the trunnion 23 and in the axial direction. The shift control valve 46 is axially displaced according to the displacement.

On the other hand, as shown in FIG. 2, the power circulation mode clutch 9 and the direct coupling mode clutch 10 for switching the direct coupling mode and the power circulation mode sandwich the planetary gear mechanism 5 between them.
It is coaxially arranged on the VT output shaft 6.

The power circulation mode clutch 9 is engaged when the clutch pressure (control pressure) Pprc supplied to the oil chamber 9a opposes the return spring 9b and presses the piston, so that the clutch pressure Pprc is increased. The clutch capacity is increased to change from the disengaged state to the engaged state.

Similarly, the direct coupling mode clutch 10 has the oil chamber 10
The clutch pressure Pdc supplied to a is pressed against the return spring 10b to press the piston to perform the engagement, and the clutch capacity is increased in accordance with the increase of the clutch pressure Pdc to change from the released state to the engaged state.

The power circulation mode clutch 9,
The direct coupling mode clutch 10 is both in the released state when the inhibitor switch 84 (see FIG. 3) that responds to the operation of the select lever is in the neutral position N or the parking position P, and is in the forward position D when either of them is released. One clutch is engaged, the power circulation mode clutch 9 is engaged at the reverse position R, and when the vehicle starts, as shown in FIG. 24, the gear shift is started from the geared neutral point GNP in the power circulation mode.

As shown in FIG. 3, the IVT shift control is as follows.
The IVT input shaft 1 or C is performed by a control unit 80 mainly composed of a microcomputer.
Rotational speed Ni of the VT input shaft 1b (= engine rotational speed Ne)
Output from the first rotation speed sensor 81 and the rotation speed No. of the continuously variable transmission output shaft 4 or the output sprocket 2a.
Of the output of the continuously variable transmission output shaft from the second rotation speed sensor 82 and the rotation speed of the IVT output shaft 6 and the like to detect the vehicle speed VSP.
Output from the vehicle speed sensor 83 for detecting the accelerator pedal depression amount AP detected by the accelerator opening sensor 85
S and the shift position POS or the like from the inhibitor switch 84 that responds to the operation of a shift lever (not shown) are input. Since the IVT input shaft 1 and the CVT input shaft 1b are directly connected to the engine, the input shaft speed Ni and the engine speed Ne of the continuously variable transmission mechanism 2 are equivalent.

The control unit 80 processes these detected values as an operating state, and drives the solenoids 91 and 92 by duty control according to the operating state, whereby the power circulation mode clutch 9 and the direct connection mode clutch 10 are driven.
The signal pressure is controlled so as to selectively engage the power circulation mode and the direct connection mode.

Then, the IVT ratio (IV
The step motor 36 so that the speed ratio of the T input shaft 1 and the IVT output shaft 6 = the total speed ratio, which will be referred to as the IVT ratio hereinafter).
By driving the gear ratio ic of the continuously variable transmission 2 (hereinafter,
CVT ratio).

The detection value P of the inhibitor switch 84
As described above, the OS sets the forward drive position to the D range, the backward drive position to the R range, the neutral position to the N range, and the parking position to the P range.

<A. Hydraulic Control> Next, the hydraulic control device will be described in detail with reference to FIG.

First, in the hydraulic control device, the hydraulic pressure supplied from the hydraulic pump is adjusted to a predetermined pressure by the pressure regulator 100 controlled by the signal pressure of the PL solenoid 90 and supplied to the line pressure circuit 101 as the line pressure PL. To be done.

The line pressure circuit 101 is connected to the shift control valve 46 for controlling the flow rate and the supply direction to the hydraulic cylinder 30 which drives the trunnion 23, and as described above, the control unit via the speed change link 37. According to the displacement of the step motor 36 or the feedback link 38 controlled by 80, the spool 4
6S is displaced, and the line pressure PL corresponding to the displacement amount of the spool 46S is applied to the two oil chambers 30A and 30B of the hydraulic cylinder 30.
Supply to one of them.

Further, the line pressure circuit 101 is provided with a solenoid 92 for controlling the power circulation mode clutch 9 and a solenoid 91 for controlling the direct coupling mode clutch 10. These solenoids 91, 92 are duty controlled by the control unit 80. To be done.

The control valve 94 regulates the line pressure PL from the manual valve 60 according to the signal pressure from the solenoid 92 driven by the duty control, and supplies it to the power circulation mode clutch 9 as the clutch pressure Pprc.
The engagement and disengagement are performed, and the clutch pressure Pprc also increases due to the increase in the signal pressure, the power circulation mode clutch 9 is engaged from the disengaged state, and the torque transmission capacity increases in accordance with the clutch pressure Pprc. When the signal pressure from the solenoid 92 decreases, the clutch pressure Pprc also decreases, and the control valve 94 connects and releases the oil chamber 9a (see FIG. 2) of the power circulation mode clutch 9 to the drain side.

Similarly, the control valve 93 regulates the line pressure PL from the manual valve 60 in accordance with the signal pressure from the solenoid 91 and supplies it as the clutch pressure Pdc to the direct coupling mode clutch 10 to perform engagement and disengagement. Therefore, when the signal pressure from the solenoid 91 increases, the clutch pressure Pdc also increases and is engaged from the released state, and the torque transmission capacity increases according to the clutch pressure Pdc, while the signal pressure decreases, the clutch pressure Pdc also decreases. Therefore, the control valve 9
3 is an oil chamber 10a of the direct coupling mode clutch 10 (see FIG. 2)
Connect to the drain side and release.

As described above, one of the power circulation mode clutch 9 and the direct coupling mode clutch 10 is engaged by the duty control of the solenoids 92 and 91, and the power circulation mode and the direct coupling mode are selectively switched, and the solenoids are operated. It is possible to control the transmission torque according to the duty ratio of 91, 92.

Here, the shift control valve 46
Is a supply port 46P communicating with the line pressure circuit 101.
A Lo-side port 46L that communicates with the oil chamber 30A of the hydraulic cylinder 30, a Hi-side port 46H that communicates with the oil chamber 30B of the hydraulic cylinder 30, and two drain ports 46.
D and 46D are provided so as to sandwich the supply port 46P, and from the supply port 46P to the Lo side port 46L or the Hi side port 46 depending on the axial displacement of the spool 46S.
The line pressure PL is regulated and supplied to one of the H ports, while the other port communicates with the drain port 46D.

On the other hand, when the spool 46S is at the neutral position, the supply port 46P, the drain port 46D, Lo.
The side port 46L and the Hi side port 46H are sealed.

From this neutral position, the spool 46 moves upward in the drawing.
When S is displaced, the supply port 46P and the Lo side port 46
While L communicates, the Hi side port 46H communicates with the drain port 46D, and the flow rate according to the opening amount of the supply port 46P and the differential pressure (pressure difference) between the supply port 46P and the Lo side port 46L is supplied to the Lo side port 46L. Supplied.

On the contrary, the spool 4 is moved downward from the neutral position in the drawing.
When 6S is displaced, supply port 46P and Hi side port 4
While 6H communicates, the Lo side port 46L communicates with the drain port 46D, and the flow rate according to the opening amount of the supply port 46P and the differential pressure (pressure difference) between the supply port 46P and the Hi side port 46H is supplied to the Hi side port 46H. Supplied.

Thus, the differential pressure is determined depending on the balance between the flow rate flowing from the supply port 46P into one of the oil chambers 30A or 30B of the hydraulic cylinder 30 and the flow rate flowing out from the other of the oil chambers 30A or 30B to the drain port 46D.

Now, when the target CVT ratio tic changes to the Lo side, the step motor 36 decreases the number of steps Step and one end of the speed change link 37 is displaced upward in FIG. 5 according to the target CVT ratio tic. Let

At this time, if the tilt angle of the power roller 20 is in a steady state, the recess cam 35 is stopped, so the spool 46S is also displaced upward, and the supply ports 46P and L are fed.
While the o-side port 46L communicates, the Hi-side port 46H
Communicates with the drain port 46D, and the oil pressure in the oil chamber 30A increases in accordance with the flow rate supplied from the supply port 46P via the Lo-side port 46L.

On the other hand, the oil pressure in the oil chamber 30B is discharged from the drain port 46D, the trunnion 23 on the right side shown in FIG. 4 rises, and the power roller 20 tilts to the Lo side of the CVT ratio as the trunnion 23 rises. Roll to shift.

Then, as described above, the trunnion 23
The rotation shaft 20c of the power roller 20 is held on the same plane as the rotation shaft 1c of the input / output disk by swinging the pivot shaft 24 in accordance with the axial displacement amount of.

By driving the hydraulic cylinder 30, the trunnion 23 is displaced in the axial direction and around the axis. The displacement of the trunnion 23 is transmitted to the speed change link 37 via the feedback link 38, and the power roller 20 is tilted to the Lo side. In response to the rotation, the feedback link 38 displaces the left end portion of the speed change link 37 downward in FIG.

Therefore, the spool 46S which has been displaced upward is displaced downward toward the neutral position, and when the tilt angle of the power roller 20 matches the target CVT ratio tic, the spool 46S is driven by the precess cam 35. Then, it returns to the neutral position again, and the drive of the hydraulic cylinder 30 is stopped.

Thus, when shifting to the Lo side of the CVT ratio, first, the spool 46 is moved by the step motor 36.
By driving S, the line pressure circuit 10 is transferred to the oil chamber 30A.
While the hydraulic oil is supplied from No. 1, the pressure oil in the oil chamber 30B is discharged to the tank, and the trunnion 23 is displaced, whereby the tilt angle of the power roller 20 moves toward the Lo side.

Next, since the tilt angle of the power roller 20 and the axial displacement of the trunnion 23 are fed back to the shift control valve 46 via the recess cam 35, the feedback link 38 and the speed change link 37, the spool 46S is gradually neutralized. After returning to the position, the target CVT ratio tic commanded by the step motor 36 and the power roller 2
The actual CVT ratio according to the tilt angle of 0 can be matched.

The relationship between the target CVT ratio tic and the step number Step of the step motor 36 is determined on the basis of a map set in advance as shown in FIG.

On the other hand, when the target CVT ratio tic changes to the Hi side, the step motor 36 and the like are driven in the opposite direction to the above, and the power roller 20 tilts to the Hi side.

Further, while the vehicle in which the N range or the P range is selected is stopped, the control unit 80 releases the power circulation mode clutch 9 to release the connection between the engine side and the drive wheel side, and at the same time, geared neutral. The gear ratio ic of the continuously variable transmission mechanism 2 is adjusted so as to maintain the point GNP (the power circulation mode clutch remains engaged while the vehicle is stopped with the D range selected).

When the vehicle is started, the solenoid 92 is controlled to gradually engage the power circulation mode clutch 9 based on the shift position POS corresponding to the shift lever, the actual CVT ratio, and the engine speed Ne. IV
The step motor 36 is controlled so that the T ratio becomes a target value according to the operating state.

<B. Input torque direction of continuously variable transmission> Here, the driving force input to the continuously variable transmission mechanism 2 adopted in the IVT, that is, the input torque, is the input torque from the engine from the input disk 21 to the output disk in the direct coupling mode. 22 is transmitted.

However, in the power circulation mode, forward and reverse are switched with the geared neutral point GNP as a boundary, so that the input torque to the continuously variable transmission mechanism 2 is
Torque is transmitted from the input disk 21 to the output disk 22 when moving backward, and assuming that the direction of this input torque is the forward direction, when moving forward, the output disk 22 moves to the input disk 2
The torque is transmitted to 1, and the direction of the input torque is the negative direction.

In the power circulation mode, as shown in FIGS. 6 and 7, the difference between the output shaft rotation speeds of the continuously variable transmission mechanism 2 and the constant transmission mechanism 3 which are input to the planetary gear mechanism 5, that is, the rotation of the sun gear 5a. The ring gear 5 coupled to the IVT output shaft 6 according to the difference between the speed and the revolution speed of the pinion of the carrier 5b.
The rotation direction of c is determined.

When the planetary gear mechanism 5 is viewed from the right side in FIG. 6 (the output gear 7 side of the continuously variable transmission) in FIG. 6, the result is as shown in FIG. 7, and the speed and direction of each rotary element are indicated by solid lines in the figure. The direction of torque transmission is indicated by a broken line with an arrow, and states of forward, backward and geared neutral points are shown in (A), (B), and (C), respectively.

{B. When the revolution speed of the pinion of the carrier 5b is higher than the rotation speed of the sun gear 5a, that is, the CVT ratio of the continuously variable transmission mechanism 2 is at the forward speed of the power circulation mode, as shown in FIG. 7 (A). , Larger than the geared neutral point GNP (L
When it is on the o side), the pinion of the carrier 5b rotates counterclockwise in the figure, so that the ring gear 5c rotates counterclockwise in the figure and the final gear 12 rotates in the forward direction.

At this time, the torque transmitted to the pinion of the carrier 5b is transmitted to the ring gear 5c and the sun gear 5a. Therefore, as shown by the solid line in FIG.
The input torque to the output disk 22 is input from the output disk 22 side via the chain 40 and has a negative direction. By the way, the torque transmitted from the output disc 22 to the input disc 21 is transmitted from the CVT input shaft 1b and the IVT input shaft 1 to the constant speed change mechanism 3, and the driving force circulates.

{B. 2 Retreat} When retreating, Fig. 7 (B)
As shown in, the rotation speed of the sun gear 5a is equal to that of the carrier 5b.
24 is sufficiently higher than the revolution speed of the pinion, that is, when the CVT ratio of the continuously variable transmission 2 is on the smaller side (Hi side) than the geared neutral point GNP shown in FIG. Since the ring gear 5c rotates in the clockwise direction in the figure, the ring gear 5c also rotates in the clockwise direction in the figure, and the final gear 12 rotates in the backward direction.

At this time, since the torque transmitted to the sun gear 5a is transmitted to the carrier 5b and the ring gear 5c, the input torque to the continuously variable transmission mechanism 2 is the input disc 21 as shown by the broken line in FIG. The torque that is transmitted in the positive direction from the output gear 22 to the output disk 22 and is transmitted to the carrier 5b through the sun gear 5a is C through the constant speed change mechanism 3.
Circulation from the VT input shaft 1b to the input disk 21 again.

{B. 3 geared neutral point} On the other hand, as shown in FIG. 7 (C), when the rotation speed of the sun gear 5a and the revolution speed of the pinion of the carrier 5b reach a value corresponding to the gear ratio of the sun gear 5a and the ring gear 5c,
The pinion of the carrier 5b rotates clockwise in the figure,
The ring gear 5c stops, and the torque from the engine circulates only from the sun gear 5a to the carrier 5b. While the final gear 12 is stopped, the continuously variable transmission 2
Then, the IVT ratio becomes infinite.

<C. Torque Shift Hysteresis> Next, the torque shift that occurs in the toroidal-type continuously variable transmission mechanism 2 will be described.

In the toroidal type continuously variable transmission mechanism 2, a phenomenon known as a torque shift in which the gear ratio changes in accordance with a change in input torque has been conventionally known. The tilt angle of the roller 20 deviates from the CVT ratio set by the step motor 36, and there are the following three factors as the cause of this torque shift.

First, in FIG. 4, when torque from the engine is applied to the input disk 21, the power roller 20 is affected by the torque, that is, the direction in which the torque is applied, that is,
The input disc 21 is displaced in the rotational direction, and an offset occurs between the rotary shaft 20c of the power roller 20 and the rotary shaft 1c of the input / output disc.
3 moves up and down. In this example, the trunnion 2 on the right side of the figure
3, the trunnion 23 on the left side in the figure descends.

Therefore, the precess cam 35 provided in the trunnion 23 on the right side in the figure moves to the Lo side (gear ratio = large side) of the CVT ratio, and as shown in FIG. 5, the spool 46S of the shift control valve 46 is moved. By displacing, hydraulic pressure is supplied to the hydraulic cylinder 30, and the power roller 20 tilts to the Lo side.

Here, the trunnion 23 based on the input torque
Of the rotating shaft 20 of the power roller 20 in a state where the ascending force (or descending force) of the power roller 20 and the differential pressure in the hydraulic cylinder 30 are balanced.
The gear shift ends when there is no offset between c and the rotary shaft 1c of the input / output disk.

When the power roller 20 is offset with respect to the input torque, tilting of the pivot shaft 24 occurs in the vertical direction of FIG. 4, and the trunnion is tilted by the tilt of the pivot shaft 24 with respect to the actual offset of the power roller 20. The axial displacement of 23 is reduced.

As a result, the amount of feedback from the precess cam 35 to the shift control valve 46 becomes small, so that the hydraulic pressure generated in the hydraulic cylinder 30 becomes small relative to the actual offset amount of the power roller 20, and the trunnion 23 described above. Lifting force and hydraulic cylinder 3
In order to balance the differential pressure within 0, a feedback amount larger than the actual axial displacement amount of the trunnion 23 is required. Therefore, in order to generate this feedback amount, the power roller 20 is tilted more. Then, the gear will be further shifted. This is the first factor of torque shift.

Next, in order to transmit the torque by the input / output disks 21, 22 and the power roller 20, the loading cam device 13 shown in FIG. 2 generates a clamping pressure corresponding to the input torque, and the power roller 20 is turned on. It is sandwiched and pressed by the output disks 21 and 22.

Therefore, the power roller 20 receives a thrust force in the direction of being pushed out between the input / output disks 21 and 22 in FIG.

Here, the power rollers 20, 20 facing each other
The trunnions 23, 23 supporting the
Since the upper and lower sides of the pivot shaft 24 are connected via a swingable link (not shown), the trunnion 23 is deformed by the thrust force with this connecting point as a fulcrum.

Due to this modification, the position of the recess cam 35 provided at the lower end of the trunnion 23 changes, and a feedback amount is added to the spool 46S via the feedback link 38 even when the gear ratio does not change.
The hydraulic pressure is supplied to the hydraulic cylinder 30 according to the displacement of the spool 46S, and the trunnion 23 is driven in the axial direction to change the speed. This is the second cause of torque shift.

The third factor is that the power roller 20 is sandwiched and pressed by the input / output discs 21 and 22 in order to transmit the torque, but the input / output disc 21 is pressed against the output disc 22 side. As a result, the disc is deformed.

Due to this deformation, the contact position between the power roller 20 and the input / output disks 21, 22 changes, so that the pivot shaft 24 swings and the trunnion 23 displaces in the axial direction in response to this swing. The gear shift is performed in the same manner as above. This is the third factor of torque shift.

Thus, in the toroidal type continuously variable transmission,
Due to the above three factors, the gear ratio (C
A phenomenon called torque shift in which the VT ratio) fluctuates occurs.

Next, the hysteresis of torque shift will be described.

When the CVT ratio is near the geared neutral point GNP and the input torque changes including 0, the continuously variable transmission mechanism as described in "B. Input torque direction of continuously variable transmission" above. Since the direction of the input torque to 2 is reversed at the geared neutral point GNP as a boundary, a hysteresis region occurs in the torque shift as shown in FIG.

In FIG. 23, the input torque to the continuously variable transmission mechanism 2 is fixed with the number of steps Step of the step motor 36 fixed so that the geared neutral point GNP is reached when the input torque is 0 and there is no load. Is a change.

When the power roller 20 is supported by the toroidal type continuously variable transmission mechanism 2 via the pivot shaft 24 as shown in FIG. 4, the above-mentioned structure is provided between the base end of the pivot shaft 24 and the trunnion 23. As described above, the bearing is interposed to support the pivot shaft 24 swingably.

However, since the bearing has radial play (clearance) and friction, the pivot shaft 24 does not swing until the torque applied to the power roller 20 becomes larger than the play and the friction.

Therefore, in the vicinity of the geared neutral point GNP, the pivot shaft 24 does not swing until the absolute value of the input torque becomes larger than the rattling and friction around the pivot shaft 24 after the direction of the input torque is reversed. Therefore, hysteresis occurs in the torque shift.

Therefore, as shown in FIG. 23, on the increase side of the input torque (direction from negative to positive), the tilt angle of the power roller 20 decreases along the line T + in the figure, while the input torque decreases. On the side (direction from positive to negative), there is a hysteresis region in which the tilt angle of the power roller 20 increases along the line T- in the figure.

Even if an attempt is made to maintain the geared neutral point GNP on the line T + in the figure, the tilt angle that can be taken when the input torque = 0 is indefinite within the fluctuation range Δφ in the figure, so the IVT ratio is The geared neutral point GNP may deviate from the geared neutral point GNP, and a shock at the time of starting or an unintended creep torque may be generated as in the conventional example.

<D. Avoidance of Hysteresis> When the toroidal type continuously variable transmission 2 is adopted, the hysteresis region as described above exists, but as shown in FIGS. 9 and 10, in the region where the input torque is near 0, the geared neutral is obtained. Step motor 36 that can become point GNP
Due to the above hysteresis, the number of steps in
There will be many in the range from ep to Bstep.

Therefore, as shown in FIG. 8, assuming that the number of steps for realizing the geared neutral point GNP while the vehicle is stopped is Asstep, the step motor 36 is set to this Step when the vehicle is stopped in the N range or the P range. Then, the power circulation mode clutch 9 is released.

From this stopped state, when the shift lever (not shown) is operated to the D range and the vehicle starts in the forward direction, the actual tilt angle is in the fluctuation range Δφ in the figure, so Set the step motor 36 to the traveling direction of the vehicle,
That is, after the preset number of steps is sent according to the output POS of the inhibitor switch 84, the preset number of steps is similarly returned according to the traveling direction of the vehicle.

For example, when ND selection is performed and the vehicle starts in the forward direction, the number of steps of the step motor 36 is temporarily changed from Asstep in FIG. 8 for realizing the geared neutral point GNP to Bstep (solid line in the figure). The power circulation mode clutch 9 is temporarily reduced to a higher CVT ratio, which is the forward side of the power circulation mode, and before the power circulation mode clutch 9 is engaged, the number of steps is increased again to Ast.
Return to ep.

As shown in FIG. 17, the smaller number of steps of the step motor 36 is the larger side of the CVT ratio (Lo side = smaller tilt angle side), and the larger number of steps is the CVT ratio. Is smaller (Hi side = tilt angle is larger).

Therefore, the tilt angle which has become indefinite within the fluctuation range Δφ in FIG. 8 is such that the step number of the step motor 36 is at least the step number B when the input torque = 0.
By moving to the step or lower, the power roller 20
Is the maximum value of the variation range Δφ ′ due to the Bstep hysteresis in the figure, and is placed on the outer peripheral upper side of the Bstep hysteresis.

Here, the step number Asstep is preset so that the tilt angle becomes the geared neutral point GNP at the minimum value of the fluctuation range Δφ when the input torque = 0, and the input torque = When it is 0, the maximum value of the variation range Δφ of the step number Bstep is set to be equal to the minimum value of the variation range Δφ of the step number Asstep.

Then, when returning to ASTEP again, the tilt angle of the power roller 20 is A on the line of input torque = 0.
The lower side of the outer circumference of the hysteresis of the step, in other words, the minimum value of the variation range Δφ in the step number Asstep, is set to the N point which is the geared neutral point GNP.

After that, if the power circulation mode clutch 9 is engaged and the number of steps is sent to the smaller side (larger side of the CVT ratio), the CVT input torque in the negative direction will always cause the vehicle to start from the geared neutral point GNP to the forward side. The toroidal-type continuously variable transmission mechanism 2 can compensate for the shift in the gear ratio due to the torque shift, which enables smooth start, and the shock and the unintended creep due to the shift in the gear ratio as in the conventional example. Can be reliably prevented.

Immediately after the ND selection, the oil pressure is supplied to the oil chamber 9a of the power circulation mode clutch 9 and gradually engaged. During this time, the geared neutral point GNP is realized as described above. Number of steps A
After decreasing from step to a predetermined number of steps Bstep that can compensate the hysteresis due to torque shift,
Since it is returned to ASTEP again, even if the power circulation mode clutch 9 is engaged in the process of returning from Bstep to ASTEP, the side where the number of steps is reduced is the forward side of the power circulation mode. The vehicle can be propelled in the intended forward direction, and it is possible to prevent the torque from being transmitted to the side opposite to the traveling direction set by the driver as in the conventional example.

When starting on the forward side, the number of steps Bstep at which the step motor 36 is driven so as to be temporarily shifted from the number of steps Asstep that realizes the geared neutral point GNP while the vehicle is stopped is this Bst.
Upper side of outer circumference of hysteresis in ep (variation range Δφ '
Of the number of steps in the N range or the P range on the forward side is within the hysteresis variation range Δφ of the N range or the P range. The tilt angle, which has become indefinite, moves to the outside of this fluctuation range Δφ by moving to the step number Bstep, and then returns to the step number Asstep again, so that the tilt angle becomes the minimum of the hysteresis fluctuation range Δφ. Value (when input torque = 0)
Therefore, the geared neutral point GNP can be reliably achieved when the vehicle is started on the forward side.

Next, a case where the N-R selection is performed and the vehicle starts in the backward direction will be described with reference to FIG.

In the case of N-R select, from the step number Asstep in FIG. 11 for realizing the geared neutral point GNP, the step number of the step motor 36 is set to be larger than the step number as Step, contrary to the case of the N-D select. Preset to the larger side of CVT (Hi side of CVT ratio)
After temporarily increasing to step (broken line in the figure), before the power circulation mode clutch 9 is engaged, it is decreased to a predetermined step number Bstep for realizing the geared neutral point GNP in the reverse direction.

Therefore, when the vehicle is stopped in the N range or the P range, the tilt angle which has become indefinite within the variation range Δφ of the step number Asstep shown in FIG. By moving to the Cstep set to the larger side of the number, Cstep in the figure
Of the hysteresis of, the outer lower side = the minimum value of the fluctuation range Δφ ″.

After this, the number of steps Cstep to Ast
The step angle is set to a smaller number of steps than ep, and the tilt angle of the power roller 20 is reduced to Bstep that realizes the geared neutral point GNP when transmitting torque in the backward direction of the vehicle, so that the tilt angle of the power roller 20 is Bstep in the figure. Of the hysteresis of, the upper side of the outer circumference = the N point that is the maximum value of the fluctuation range Δφ.

At the upper side of the outer circumference of this Bstep, the variation range Δ
Since the maximum value of φ ′ passes through the geared neutral point GNP when the CVT input torque increases in the positive direction (reverse side of the power circulation mode), after that, the power circulation mode clutch 9 is engaged and the number of steps is increased. Is transmitted to the large side (small side of the CVT ratio), the CVT input torque in the positive direction always allows the vehicle to start in the reverse direction from the geared neutral point GNP, and the toroidal type continuously variable transmission even when the vehicle reverses. It is possible to compensate for the shift in the gear ratio due to the torque shift peculiar to the mechanism 2 to enable a smooth start, and reliably prevent the shock and the unintended creep due to the shift in the gear ratio as in the conventional example.

Immediately after the N-R selection, the oil pressure is supplied to the oil chamber 9a of the power circulation mode clutch 9 and gradually engaged. During this time, the geared neutral point GNP is realized as described above. Number of steps A
After increasing from Cstep to Cstep on the larger step side, it is reduced to a predetermined step number Bstep capable of compensating the hysteresis due to torque shift. Even if the circulation mode clutch 9 is engaged, the side in which the number of steps is larger than Asstep is the backward side in the power circulation mode, so that the vehicle can be propelled in the backward direction intended by the driver, as in the conventional example. It is possible to prevent the torque from being transmitted to the side opposite to the traveling direction set by the driver.

Here, the number of steps Cstep for temporarily driving the step motor 36 at the time of starting to the reverse side is
As mentioned above, Bs on the smaller step side than Asstep
When moving to step, the outer peripheral lower side of the hysteresis at the number of steps Cstep = the minimum value of the fluctuation range Δφ is smaller than the maximum outer peripheral side of the hysteresis at the finally moved Bstep = the maximum value of the fluctuation range Δφ. It suffices if it is on the large side, and the tilt angle, which was indefinite in the hysteresis variation range Δφ when the number of steps Asstep, is always the upper outer side of the hysteresis (variation range) in Bstep when moving from the number of steps Cstep to Bstep. It is possible to realize the geared neutral point GNP on the reverse side by riding on (maximum value of Δφ ′).

Thus, before the power circulation mode clutch 9 is engaged, the geared neutral point GNP is set.
After the step motor 36 is temporarily driven from the preset number of steps Asstep to the outside of the variation range Δφ according to the magnitude of hysteresis according to the traveling direction of the vehicle, the step motor 36 is set according to the traveling direction. By moving to the step number, the tilt angle of the power roller 20 is set outside the variation range Δφ of the step corresponding to the geared neutral point GNP, and then the step number Asstep set again according to the traveling direction is set. Or Bstep
When the input torque is 0, the tilt angle is set to either the minimum value or the maximum value of the fluctuation range Δφ, and the vehicle can reliably start from the geared neutral point GNP.

In FIG. 11, the N range or P
The case where the number of steps for realizing the geared neutral point GNP in the range is set to Asstep is shown, but the geared neutral point GNP may be realized for the number of steps Bstep while the vehicle is stopped. In this case, NR select Once done, Bstep to As
After increasing the number of steps once until step, B again
It suffices to engage the power circulation mode clutch 9 after returning to step, and in the same manner as above, the hysteresis of the torque shift can be avoided and the start can be reliably performed from the geared neutral point GNP, and the step motor 36 Even if the power circulation mode clutch 9 is engaged while the number of steps is increased or decreased, torque can be transmitted to the reverse side to propel the vehicle in the reverse direction intended by the driver. Thus, it is possible to prevent the torque from being transmitted to the side opposite to the traveling direction set by the driver.

Next, an example of the starting control performed by the control unit 80 will be described in detail below with reference to the flow charts of FIGS.

Each flowchart is executed every predetermined time, for example, every 10 msec from the selection operation until the power circulation mode clutch 9 is completely engaged. FIG. 13 is a subroutine showing the control of the step motor 36 according to the select operation, and the flow chart of FIG. 14 similarly shows the engagement control of the power circulation mode clutch 9 according to the select operation.

First, in step S30 of FIG. 12, the shift position POS from the inhibitor switch 84 is read, and then in step S31, the shift position POS is ND.
When the selection or the N-R selection is performed, the step number of the step motor 36 is controlled to be temporarily increased or decreased.

Then, in step S32, when ND selection or NR selection is performed, hydraulic control for gradually engaging the power circulation mode clutch 9 is performed.

Next, in the control of the step motor 36 shown in FIG. 13, first, in step S40, it is determined whether or not it is in the N range or the P range, and if it is in the N or P range,
While proceeding to step S42 to perform processing while the vehicle is stopped, N-
When the D (P-D) selection or the N-R (P-R) selection is performed, the process proceeds to step S44, and shift control for starting the start is performed.

In the processing at step S42 while the vehicle is stopped, the number of steps Step of the step motor 36 is set to the number of steps Sn which is the preset geared neutral point GNP, and then the timer tc1 is cleared to 0 and the processing is ended. .

The geared neutral point GN
The step number Sn corresponding to P is set to, for example, the step number Asstep shown in FIGS.

Then, in step S44 for starting the start,
The select operation determines whether the D range is the R range, and if the D range is the D range, the process proceeds to step S45 to set the increase / decrease amount ΔSTP per control cycle to a preset negative value, for example, −1. The CVT ratio is set to be temporarily high.

On the other hand, if the range is not the D range, the process proceeds to step S46 to determine whether the selection operation is the R range. If the range is the R range, the process proceeds to step S47 to preset the increase / decrease amount ΔSTP per control cycle. Is set to a positive value, for example, +1 so that the CVT ratio is temporarily on the high side.

The increase / decrease amount ΔSTP is an example when the step number Step and the CVT ratio of the step motor 36 are set as shown in FIG.

Next, at step S48, the timer tc1
Is incremented according to the control cycle Δt (here, 10 msec), and then in step S49, the timer tc1
It is determined whether the elapsed time of is less than or equal to a preset value Time_a, and if the timer tc1 is less than or equal to Time_a, as shown in FIGS.
It is determined that it is time to shift to the outside of the variation range Δφ according to the hysteresis of, and the process proceeds to step S50.

In step S50, the above step S45 is performed.
Alternatively, the increase / decrease amount ΔSTP set in S47 is added and the number of steps S of the step motor 36 is changed according to the traveling direction of the vehicle.
Change the step and end the processing.

On the other hand, if it is determined in step S49 that the timer tc1 exceeds the preset value Time_a, the process proceeds to step 51 and subsequent steps, and the number of steps corresponds to the geared neutral point GNP according to the traveling direction. Control to return to Sn. Note that N-
At the time of R selection, the number of steps Sn to be restored is set to the number of steps Bstep shown in FIG. 11, for example.

That is, in step S51, the increase / decrease amount ΔSTP is subtracted for each control cycle from the step number Step of the step motor 36, and after the step number Step of the step motor 36 exceeds Sn in steps S52 and S53, the step The number is returned to Sn corresponding to the geared neutral point GNP, and the process ends.

Next, the engagement control of the power circulation mode clutch 9 which is performed at the time of starting the vehicle is performed in the step S60 of FIG.
It is determined whether or not the selection or the N-R selection is performed, and when the output POS of the inhibitor switch 84 is in the N range or the P range, the hydraulic pressure command to be supplied to the power circulation mode clutch 9 is advanced to step S61. The value (hereinafter, referred to as clutch pressure) Pprc is set to 0, and in step S62, N-D select or N-
A timer tc2 for measuring the elapsed time from R select is reset to 0.

On the other hand, in step S63 in which ND select or NR select is detected, the clutch engagement control is performed according to the elapsed time. Therefore, after incrementing the timer tc2 in accordance with the control cycle, in step S64, It is determined whether or not the value of the timer tc2 has passed the first predetermined time TIME1, and if it is less than the predetermined time TIME1, it is determined that the selection operation has just been performed, and step S6 is performed.
On the other hand, if the predetermined time TIME1 has elapsed while proceeding to step 5, the process proceeds to step S66.

In step S65 immediately after the select operation,
Clutch pressure Ppr supplied to the power circulation mode clutch 9
c is set to a predetermined precharge pressure (intermediate pressure) PRS # PRE, and the process is ended.

Since the clutch pressure Pprc is almost 0 in the N range or the P range in the power circulation mode clutch 9, as shown in FIG. 2, the power circulation mode clutch 9 is pressed by the spring 9b and pressed rightward in the drawing. The member 9c is separated from the disc 9d and is in the released state. Therefore, as shown in FIG. 15 or FIG. 16, the command value is raised to the precharge pressure PRS # PRE and the pressure oil is quickly supplied to the oil chamber 9a, but the command value becomes the precharge pressure PRS # PRE. However, the power circulation mode clutch 9 does not generate an engagement force, and the actual hydraulic pressure gradually rises as shown by the broken lines in FIGS. 15 and 16 toward the return pressure PRS # RMP described later.

The elapsed time of the shift control Time_
a is set to a value smaller than the first predetermined time TIME1.

Next, in step S66 after the lapse of the first predetermined time TIME1, it is determined whether or not the value of the timer tc2 has passed the second predetermined time TIME2, and if it is less than the predetermined time TIME2, the precharge is performed. While it is determined that the process is completed, the process proceeds to step S67, while if the predetermined time TIME2 has elapsed, the process proceeds to step S68.

At the step S67 of ending the precharge,
Clutch pressure Ppr supplied to the power circulation mode clutch 9
c is set to a predetermined return pressure (intermediate pressure) PRS # RTN, and the process is ended. This return pressure PRS #
RTN is a critical pressure at which the piston 9p presses the disc 9d against the spring 9b to generate a fastening force.

On the other hand, in step S68 when the second predetermined time TIME2 has elapsed, it is determined whether or not the value of the timer tc2 has passed the third predetermined time TIME3. If it is less than the predetermined time TIME3, the process proceeds to step S69. While proceeding
If the predetermined time TIME3 has elapsed, step S72
To the hydraulic pressure PRS # for which the clutch pressure Pprc has been preset.
The speed is increased to MAX, the clutch is engaged according to the input torque, and the engagement force control during normal running is performed thereafter. In addition, in the shift control, after a predetermined time TIME3 has passed, normal shift control, that is, control of the CVT ratio is performed so that the IVT ratio becomes the IVT ratio according to the operating state such as the vehicle speed and the input torque.

In steps S69 to S71, the clutch pressure Pprc is the preset shelf pressure P from the return pressure PRS # RTN.
To the RS # LMT, it is ramped up by a predetermined increment value PRS # RMP. Here, the shelf pressure PRS # LMT is a hydraulic pressure with which the power circulation mode clutch 9 is completely engaged.

Therefore, the above steps S69 to S71.
Then, the clutch pressure Pprc supplied to the power circulation mode clutch 9 gradually increases from the return pressure PRS # RTN to the shelf pressure PRS # LMT according to the predetermined increment value PRS # RMP, and the power circulation mode clutch 9 The tightening force of is gradually increased, and the transmission torque is gradually increased to prevent the engine from stalling and smoothly start the vehicle.

During the predetermined time TIME1 to TIME3 when the driver performs the ND select operation, the clutch pressure Pprc supplied to the power circulation mode clutch 9 is gradually increased as shown in FIG. The start can be smoothly performed, and each predetermined time TIME1 to TIME3
As shown in the figure, PRS #
It is set as RTN <PRS # PRE <PRS # LMT <PRS # MAX, and is set to, for example, about 1 second from the time T = 0 immediately after the selection operation to the time TIME3 when the fastening is completed.

In the shift control for avoiding the hysteresis, the clutch pressure Pprc is the precharge pressure PRS # PR.
After the CVT ratio is temporarily increased or decreased within the elapsed time Time_a that is less than the elapsed time TIME1 set to E, the clutch pressure Pprc changes from the return pressure PRS # RTN to the shelf pressure P.
Time TI to start rising (ramp control) toward RS # RMP
It is sufficient to return to the step number Sn (= Astep) corresponding to the geared neutral point GNP by ME2. The precharge time TIME1 is set to, for example, 30 to 50 msec.

Therefore, when the ND select is advanced, as shown in FIG. 15, during the precharge period, the CVT ratio is temporarily shifted to the large side (the number of steps is the small side), and then the step corresponding to the geared neutral point GNP is performed. Since the engaging force of the power circulation mode clutch 9 is generated after returning to the number Sn, as described above, the geared neutral point G due to the hysteresis of the torque shift.
It is possible to start the vehicle while reliably preventing the NP from changing, and it is possible to improve the starting performance of the IVT in which the toroidal type is adopted for the continuously variable transmission mechanism 2.

Similarly, when the N-R select is retracted, as shown in FIG.
As shown in 6, after the CVT ratio once shifts to the small side (the number of steps is large) during the precharge period, the number of steps Sn (= B) corresponding to the geared neutral point GNP is set.
Since the engaging force of the power circulation mode clutch 9 is generated after returning to the step), the geared neutral point GNP due to the hysteresis of the torque shift.
Therefore, it is possible to start the vehicle while surely preventing the fluctuations in the IVT, and it is possible to improve the starting performance of the IVT in which the toroidal type is adopted for the continuously variable transmission mechanism 2.

In the above embodiment, the clutch pressure Pp
Although the control of rc was given priority, although not shown, the control of the clutch pressure Pprc is performed after waiting for the temporary increase / decrease of the gear ratio to be completed and returning to the step number Sn that becomes the geared neutral point GNP. The same effect can be obtained, and if the maximum value of the increasing / decreasing step number is set to be large, the variation of the geared neutral point GNP due to hysteresis can be prevented more reliably.

FIG. 18 shows the second embodiment, in which the temporary increase / decrease of the CVT ratio in the second embodiment is stopped,
The number of steps Sn is set so that the geared neutral point GNP is obtained at a position outside the hysteresis region.

In this case, the torque Ti1 is transmitted immediately after the engagement of the power circulation mode clutch 9 is started, and in order to mitigate the shock at the time of starting, the above-mentioned FIG.
5, predetermined time TIME2 to TIME3 shown in FIG.
The ramp control up to is only required to be performed gently, and the geared neutral point G due to the hysteresis of the torque shift.
It is possible to start the vehicle while reliably preventing the NP from changing, and it is possible to improve the starting performance of the IVT in which the toroidal type is adopted for the continuously variable transmission mechanism 2.

19 and 20 show a third embodiment,
The number of steps Bste shown in FIG. 8 of the first embodiment.
The vehicle is started on the forward side with p, and is started on the backward side with the step number Asstep. The relationship between the number of steps Asstep and Bstep is the same as in the first embodiment, and the minimum value of the variation range Δφ in Asstep is set equal to the maximum value of the variation range Δφ in Bstep.

As in the first embodiment, the number of steps for realizing the geared neutral point GNP is Ast.
In the N range or the P range, the step motor 36 is set to this Step to release the power circulation mode clutch 9.

First, when ND select is performed and the vehicle starts in the forward direction, as shown in FIG. 19, Aste in FIG. 19 for realizing the geared neutral point GNP.
From p, the number of steps of the step motor 36 is set to Bstep
(Solid line in the figure), and after changing to the large side of the CVT ratio which is the forward side of the power circulation mode, the power circulation mode clutch 9 is engaged to start.

The tilt angle which has been indefinite within the variation range Δφ of the step number Asstep is as follows:
By moving the number of steps of the step motor 36 to at least the number of steps Bstep, the maximum value of the variation range Δφ ′ due to the hysteresis of Bstep in the figure becomes,
It is always set to the N point on the upper side of the outer periphery of the Bstep hysteresis.

After that, if the number of steps is sent to the smaller side (the larger side of the CVT ratio) while controlling the engagement capacity of the power circulation mode clutch 9, the CVT input torque in the negative direction always causes the vehicle to move forward from the geared neutral point GNP. Can be started to the side, the shift of the gear ratio due to the torque shift peculiar to the toroidal type continuously variable transmission mechanism 2 can be compensated to enable smooth start, and the shock due to the shift of the gear ratio as in the prior art example. It is possible to reliably prevent unintended creep.

When the step number Bstep is advanced, the number of steps is reduced to B1 in the figure,
By gradually increasing the engagement force of the power circulation mode clutch 9, the relationship between the tilt angle and the torque is changed from D1 to D in the figure.
The transmission torque in the forward direction can be gradually increased by gradually changing to 2, D3. When the vehicle is stopped by depressing the brake pedal, this transmission torque becomes creep torque, so the number of steps can be reduced. The creep torque can be controlled by controlling the engagement force of the power circulation mode clutch 9 while sending the creep torque.

If the power circulation mode clutch 9 is gradually released from the tilt angle at the point D3 in the figure, the relationship between the tilt angle and the torque changes from D3 to D2 and D1 in the figure, and the creep torque is changed. Can be reduced according to the engagement force of the power circulation mode clutch 9. That is, the creep torque can be controlled with high reproducibility for each number of steps.

Next, a case where the N-R selection is performed and the vehicle starts in the backward direction will be described with reference to FIG.

In the case of NR selection, as shown in FIG. 20, the number of steps of the step motor 36 is reduced to Bstep (the one-dot chain line in the figure) from Asstep of FIG. 20 for realizing the geared neutral point GNP, and the power is changed. Change to the higher side of the CVT ratio which is the forward side of the circulation mode,
By returning to the step number Asstep again, while the vehicle is stopped,
The tilt angle that has become indefinite within the variation range Δφ of the step number Asstep is such that the step number of the step motor 36 is at least the step number Bstep when the input torque = 0.
After returning to Step, the tilt angle becomes the minimum value of the variation range Δφ due to the hysteresis of Step in the figure, and is always set to the N point on the lower outer peripheral side of the hysteresis of Step.

After that, if the number of steps is sent to the large side (small side of the CVT ratio) while controlling the engagement capacity of the power circulation mode clutch 9, the CVT input torque in the forward direction always causes the geared neutral point GNP to retreat. Can be started to the side, the shift of the gear ratio due to the torque shift peculiar to the toroidal type continuously variable transmission mechanism 2 can be compensated to enable smooth start, and the shock due to the shift of the gear ratio as in the prior art example. It is possible to reliably prevent unintended creep.

When reversing from the step number Asstep, with the number of steps set to A1, the engagement force of the power circulation mode clutch 9 is gradually increased so that the relationship between the tilt angle and the torque is shown in the figure. Points D1 to D
The transmission torque in the reverse direction can be gradually increased by gradually changing to 2, D3, and when the vehicle is stopped by depressing the brake pedal, this transmission torque becomes creep torque, so the number of steps is increased. The creep torque can be controlled by controlling the engagement force of the power circulation mode clutch 9 while sending the creep torque.

Further, when the power circulation mode clutch 9 is gradually released from the tilt angle D3 in the figure, the relationship between the tilt angle and the torque changes sequentially from D3 to D2 and D1 in the figure to increase the creep torque. It can be reduced according to the engagement force of the power circulation mode clutch 9. That is, the creep torque can be controlled with high reproducibility for each number of steps.

21 and 22 show the fourth embodiment,
The vehicle is started at the end of the hysteresis region.

First, the ND select of FIG. 21 will be described. When the N or P range is stopped, the geared neutral point GNP is realized by the number of steps Asstep, as in the first embodiment.

When the ND select is performed and the vehicle starts in the forward direction, as shown in FIG. 21, the step number of the step motor 36 is reduced to Estep (broken line in the figure) from the step number Asstep. After that, the number of steps is increased to Dstep, and then the power circulation mode clutch 9 is engaged to start the vehicle.

The tilt angle which has become indefinite within the variation range of the step number Asstep is reduced to Dstep after the step number of the step motor 36 is reduced to Eststep in the state where the input torque is 0. It becomes the minimum value of the variation range Δφ due to the Dstep hysteresis, and is always set to the Nb point on the lower side of the outer periphery in the Dstep hysteresis.

Here, the number of steps Dstep is the region where the input torque is negative, and is the end point of the hysteresis region (N in the figure).
Point) is set to be the geared neutral point GNP.

On the other hand, at the point Nb, the tilt angle is deviated from the geared neutral point GNP to the forward side (smaller number of steps) in the power circulation mode.

At this time, when the power circulation mode clutch 9 is gradually engaged, the vehicle is stopped, so that the IVT ratio is inevitably at the geared neutral point GNP, and the tilt angle is on the lower outer periphery of the step number Dstep. Following this, the vehicle moves from the point Nb to the point Nc in the figure to the point N preset as the geared neutral point GNP.

That is, by controlling the engagement capacity, it is possible to avoid the hysteresis region and reliably start from the geared neutral point GNP.

Then, if the number of steps is reduced from this N point, it is possible to reliably start the vehicle on the forward side.

For example, if the number of steps is decreased from Dstep to Estep in the figure, the tilt angle is changed from N point to N step in the figure.
By moving to point d, shift control can be performed without being affected by hysteresis due to torque shift.

Here, as shown in FIG. 8 of the first embodiment, when starting from the step number Asstep to the forward side, the tilt angle is controlled from the point Na in FIG.

When the number of steps is reduced toward the forward side,
Due to the hysteresis, there is a steep slope portion X in which the rate of change of the tilt angle with respect to torque increases. Therefore, in this section X, the tilt angle is G unless the step motor 36 is rapidly moved.
There is a case where it enters the retreat side rather than the NP.

On the other hand, as shown in FIG. 21, at the point N of the step number Dstep, the vehicle is started after passing the section Nc-N which is already a steep slope, so that it depends on the step number and the input torque. It suffices to determine the speed of the step motor 36 in accordance with the above, and it is not necessary to increase the driving speed of the step motor 36 in accordance with the steep slope X as described above.

Next, the case where the N-R selection is performed and the vehicle starts in the backward direction will be described with reference to FIG.

In FIG. 22, the geared neutral point GNP is realized by the number of steps Bstep while the N or P range is stopped.

Geared neutral point G while stopped
From Bstep of FIG. 21 that realizes NP, the number of steps of the step motor 36 is increased to Gstep (broken line in the figure), and it is changed to the smaller side of the CVT ratio which is the backward side of the power circulation mode, and again to the step number Fstep. When the vehicle is stopped, the tilt angle, which was indefinite within the fluctuation range of the step number Bstep when the vehicle was stopped, is the input torque = 0, and the step number of the step motor 36 is at least the step number Gst.
After moving to ep, by returning to Fstep, the tilt angle changes in the range Δ due to the hysteresis of Fstep in the figure.
It becomes the maximum value of φ, and is always set to the Nb point on the outer peripheral upper side of the Fstep hysteresis.

Here, the number of steps Fstep is the region where the input torque is positive and is the end point of the hysteresis region (N in the figure).
Point) is set to be the geared neutral point GNP.

On the other hand, at the point Nb in the figure, the tilt angle is deviated from the geared neutral point GNP to the backward side (larger number of steps) in the power circulation mode.

At this time, when the power circulation mode clutch 9 is gradually engaged, the vehicle is stopped, so the IVT ratio must be the geared neutral point GNP, and the tilt angle is on the upper outer periphery of the step number Fstep. Following this, the vehicle moves from the point Nb to the point Nc in the figure to the point N preset as the geared neutral point GNP.

That is, by controlling the engagement capacity, it is possible to reliably start from the geared neutral point GNP while avoiding the hysteresis region.

If the number of steps is increased from this N point, it is possible to reliably start the vehicle in the backward direction.

For example, if the number of steps is increased from Fstep to Gstep in the figure, the tilt angle is changed from N point in the figure to N step.
By moving to the point r, the shift control can be performed without being affected by the hysteresis due to the torque shift.

Also in this case, as in the case of the forward movement, at the point N of the step number Fstep, since the section Nc-N, which is already a steep slope, has passed, the step motor is changed according to the step number and the input torque. It is only necessary to determine the speed of the step motor 36, and it is not necessary to increase the drive speed of the step motor 36 in accordance with the steep slope portion X as described above.

Thus, at the time of starting, by setting the number of steps Dstep or Fstep that realizes the geared neutral point GNP to the end point or outside the hysteresis region and setting the direction of the input torque = the starting direction, It is possible to perform shift control from the start of the start without being affected by the area,
In particular, when the oil temperature is low at which the responsiveness of the step motor 36 decreases, it is not necessary to consider the increase in speed due to the steeply sloping portion X in the hysteresis region. It is possible to obtain a response speed, improve the responsiveness of the shift control, and reduce the size and weight of the device.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention and showing a schematic configuration of an infinitely variable transmission continuously variable transmission.

FIG. 2 is a cross-sectional view of essential parts of an infinitely variable transmission continuously variable transmission.

FIG. 3 is a control block diagram of an infinitely variable transmission continuously variable transmission.

FIG. 4 is a schematic sectional view of a toroidal type continuously variable transmission.

FIG. 5 is a circuit diagram of a hydraulic control device.

FIG. 6 is a conceptual diagram of a continuously variable transmission with an infinite transmission ratio, showing the transmission of torque according to the traveling direction.

FIG. 7 is a conceptual diagram showing the operation of the planetary gear mechanism in the power circulation mode, where (A) shows forward movement, (B) shows reverse movement, and (C) shows geared neutral point GNP.

FIG. 8 is a graph showing a relationship between an input torque and a tilt angle in the vicinity of a geared neutral point GNP in a power circulation mode during ND selection.

FIG. 9 is a graph showing the relationship between the reciprocal of the IVT ratio and the number of steps of the step motor in the vicinity of the geared neutral point GNP in the power circulation mode.

FIG. 10 is a graph showing the relationship between the number of steps of the step motor and the tilt angle in the vicinity of the geared neutral point GNP in the power circulation mode.

FIG. 11 is a graph showing the relationship between the input torque and the tilt angle in the vicinity of the geared neutral point GNP in the power circulation mode during NR selection.

FIG. 12 is a flowchart showing the content of shift control performed by the control unit when the select lever is operated.

FIG. 13 is a flow chart showing a step motor control in a shift control subroutine.

FIG. 14 is likewise a flowchart showing a hydraulic control of the power circulation mode clutch in a shift control subroutine.

FIG. 15 is a graph showing the relationship between the hydraulic pressure of the power circulation mode clutch and the number of steps of the step motor during ND selection.

FIG. 16 is a graph showing the relationship between the hydraulic pressure of the power circulation mode clutch and the number of steps of the step motor during NR selection.

FIG. 17 is a map showing the relationship between the number of steps of the step motor and the CVT ratio.

FIG. 18 is a graph showing the relationship between the input torque and the tilt angle in the vicinity of the geared neutral point GNP in the power circulation mode according to the second embodiment.

FIG. 19 is a graph showing the third embodiment and showing the relationship between the input torque and the tilt angle in the vicinity of the geared neutral point GNP in the power circulation mode. In the D range, the tilt angle is the step number Bstep. The vehicle starts from the maximum value of the fluctuation range Δφ.

FIG. 20 is a graph showing the relationship between the input torque and the tilt angle in the vicinity of the geared neutral point GNP in the power circulation mode.
In step, the tilt angle starts from the minimum value of the fluctuation range Δφ.

FIG. 21 is a graph showing the relationship between the input torque and the tilt angle in the vicinity of the geared neutral point GNP in the power circulation mode according to the fourth embodiment. In the D range, the tilt angle is the step number Dstep. The vehicle starts from the minimum value of the fluctuation range Δφ.

FIG. 22 is a graph showing the relationship between the input torque and the tilt angle in the vicinity of the geared neutral point GNP in the power circulation mode.
In step, the tilt angle starts from the maximum value of the fluctuation range Δφ.

FIG. 23 is a graph showing a state of torque shift and hysteresis in the vicinity of a geared neutral point GNP when a toroidal type is adopted as a continuously variable transmission mechanism, and is a graph showing a relationship between an input torque and a tilt angle.

FIG. 24 is a graph showing the relationship between the gear ratio of a continuously variable transmission mechanism and the reciprocal of the gear ratio of an infinitely variable gear ratio continuously variable transmission.

[Explanation of symbols]

1 IVT input shaft 2 continuously variable transmission 3 constant speed change mechanism 4 continuously variable transmission output shaft 5 Planetary gear mechanism 6 IVT output shaft 9 Power circulation mode clutch 36 step motor 80 control unit 81,82 Revolution sensor 83 Vehicle speed sensor 84 Inhibitor switch

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Narita No. 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Tatsuya Nagato No. 2 Takara-cho, Kanagawa-ku, Yokohama, Nissan Nissan Motor Co., Ltd. (72) Inventor Manzaburo Abe 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (56) Reference JP-A-11-247983 (JP, A) JP-A-10-267117 (JP, A) JP 10-115357 (JP, A) JP 10-246327 (JP, A) JP 10-246326 (JP, A) Special Table 57-501039 (JP, A) (58) Survey Fields (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (10)

(57) [Claims] 1. A unit input shaft connected to an engine is connected to a toroidal type continuously variable transmission mechanism and a constant transmission mechanism, each of which can continuously change a gear ratio, and
The output shaft of the continuously variable transmission and the constant transmission is a planetary gear mechanism,
A continuously variable transmission with an infinite transmission ratio connected to a unit output shaft via a power circulation mode clutch and a direct connection mode clutch, a shift position detecting means for detecting the position of a select lever or a switch, and a transmission ratio of the continuously variable transmission mechanism. And an infinitely variable gear ratio control means for changing the total gear ratio of the infinitely variable transmission continuously variable transmission by controlling the actuator according to the operating state of the vehicle. In the control device of the machine, the gear ratio control means temporarily moves the position of the actuator when the shift position detection means detects an operation from the N range or P range to the D range or R range, A control device for a continuously variable transmission with an infinite transmission ratio, which is characterized by driving to a position that realizes a neutral point. 2. A toroidal type continuously variable transmission mechanism capable of continuously changing a gear ratio and a constant transmission mechanism are respectively connected to a unit input shaft connected to an engine, and
The output shaft of the continuously variable transmission and the constant transmission is a planetary gear mechanism,
A continuously variable transmission with an infinite transmission ratio connected to a unit output shaft via a power circulation mode clutch and a direct connection mode clutch, a shift position detecting means for detecting the position of a select lever or a switch, and a transmission ratio of the continuously variable transmission mechanism. And an infinitely variable gear ratio control means for changing the total gear ratio of the infinitely variable transmission continuously variable transmission by controlling the actuator according to the operating state of the vehicle. In the control device of the machine, the gear ratio control means changes the position of the actuator from a position corresponding to a geared neutral point when the shift position detection means detects an operation from the N range or P range to the D range or R range. After moving temporarily, it is special to drive to a position that realizes a geared neutral point when starting. Control device for continuously variable transmission with infinite gear ratio. 3. The gear ratio control means at least torque shifts when the shift position detecting means detects an operation from the N range or P range to the D range or R range to temporarily move the position of the actuator. 3. The control device for an infinitely variable transmission continuously variable transmission according to claim 1, wherein the actuator is moved to a position corresponding to the magnitude of the hysteresis. 4. The gear ratio control means, when the shift position detecting means detects an operation from the N range or P range to the D range or R range, changes the driving direction of the actuator according to the traveling direction of the vehicle. The control device for an infinitely variable transmission continuously variable transmission according to claim 2 or 3, wherein the setting is performed. 5. The gear ratio control means, when the shift position detecting means detects an operation from an N range or a P range to a D range, sets a drive position of the actuator from a position corresponding to a geared neutral point,
5. The gear ratio according to claim 4, wherein the gear is driven to a position that is set to a large side of the gear ratio of the continuously variable transmission mechanism and then to a position that achieves a geared neutral point at the time of starting. Control device for infinitely variable continuously variable transmission. 6. The gear ratio control means, when the shift position detecting means detects an operation from an N range or a P range to an R range, sets the drive position of the actuator from a position corresponding to a geared neutral point,
The gear ratio according to claim 4, wherein the continuously variable transmission is driven to a position that is set to a small side of the gear ratio and is then driven to a position corresponding to the geared neutral point when the vehicle starts. Control device for infinitely variable continuously variable transmission. 7. A unit input shaft connected to an engine is connected to a toroidal type continuously variable transmission mechanism and a constant transmission mechanism, each of which can continuously change a gear ratio, and
The output shaft of the continuously variable transmission and the constant transmission is a planetary gear mechanism,
A continuously variable transmission with an infinite transmission ratio connected to a unit output shaft via a power circulation mode clutch and a direct connection mode clutch, a shift position detecting means for detecting the position of a select lever or a switch, and a transmission ratio of the continuously variable transmission mechanism. And an infinitely variable gear ratio control means for changing the total gear ratio of the infinitely variable transmission continuously variable transmission by controlling the actuator according to the operating state of the vehicle. In the control device for a machine, the gear ratio control means realizes a geared neutral point when the input torque is 0 when the shift position detecting means detects an operation from the N range or P range to the D range or R range. The position where the actuator is driven to the position to realize this geared neutral point is the shift position detection. A control device for an infinitely variable transmission continuously variable transmission, characterized in that when the input torque changes in the traveling direction set by the means, the creep torque is controlled according to the traveling direction. 8. A toroidal type continuously variable transmission mechanism capable of continuously changing a gear ratio and a constant transmission mechanism are respectively connected to a unit input shaft connected to an engine, and
The output shaft of the continuously variable transmission and the constant transmission is a planetary gear mechanism,
A continuously variable transmission with an infinite transmission ratio connected to a unit output shaft via a power circulation mode clutch and a direct connection mode clutch, a shift position detecting means for detecting the position of a select lever or a switch, and a transmission ratio of the continuously variable transmission mechanism. And an infinitely variable gear ratio control means for changing the total gear ratio of the infinitely variable transmission continuously variable transmission by controlling the actuator according to the operating state of the vehicle. In the control device for a machine, the gear ratio control means realizes a geared neutral point in a state where the input torque is increased when the shift position detection means detects an operation from the N range or P range to the D range or R range. A control device for a continuously variable transmission having an infinite transmission ratio, characterized by driving the actuator to a position. 9. The gear ratio control means sets a position where a geared neutral point is realized in a state where the input torque is increased, outside a hysteresis region due to torque shift or at an end point of the hysteresis region. A control device for a continuously variable transmission having an infinite transmission ratio according to claim 8. 10. The gear ratio control means sets a position for realizing a geared neutral point in a state where the input torque is increased, according to a direction of the input torque to the continuously variable transmission mechanism. Item 10. A control device for an infinitely variable transmission continuously variable transmission according to Item 9.